Conventionally, industrial facilities have gas compression systems (for example, Patent Literature 1) that compress a predetermined gas, such as CO2 gas, recovered from exhaust gas discharged from industrial equipment, such as boilers and gas turbines.
FIG. 3 shows an example of the configuration of a conventional gas compression system 200. The gas compression system 200 shown in FIG. 3 compresses CO2 gas, for example.
The gas compression system 200 compresses CO2 gas with a plurality of compressors 202 (202-1 to 202-4). In addition to the plurality of compressors 202, the gas compression system 200 includes a plurality of coolers 204, a plurality of knock-out drums (gas-liquid separating devices) 206, and a dehydration equipment 208.
The coolers 204 cool the compressed CO2 gas. The knock-out drums 206 recover water (H2O) condensed due to a decrease in the degree of water saturation in the CO2 gas by compression. The dehydration equipment 208 uses a adsorbent to recover (remove) water that cannot be recovered by the knock-out drums 206. In the example in FIG. 3, the dehydration equipment 208 is provided in the middle of the plurality of compressors 202.
The dehydration equipment 208 includes adsorption towers 210 (210A and 210B), a regenerative gas heater 212, a regenerative gas cooler 214, and regenerative gas knock-out drum 216.
The adsorption towers 210 alternately perform an adsorption process, in which water contained in CO2 gas is adsorbed, and a regeneration process, in which the adsorbed water is desorbed. After completion of the regeneration process, the adsorption towers 210 perform a cooling process and a stand-by process before proceeding to the adsorption process.
For example, when the adsorption tower 210B performs the regeneration process, a portion of CO2 gas dehydrated in the adsorption tower 210A is heated to a predetermined temperature by the regenerative gas heater 212 and is supplied to the adsorption tower 210B. Thus, water is desorbed from the adsorption tower 210B.
The regenerative gas sent out from the adsorption tower 210B and containing the desorbed water is supplied to the regenerative gas cooler 214 and is cooled to a predetermined temperature. At this time, most of the desorbed water is recovered as condensed water by the regenerative gas knock-out drum 216 in the subsequent stage.
Because the water-saturated regenerative gas resulting after recovery of water by the regenerative gas knock-out drum 216 has been reduced in pressure by passing through pipes and devices, the regenerative gas is returned not to the inlet side of the compressor 202-3, which is provided in the subsequent stage of the compressor 202-2 that supplies CO2 gas to the dehydration equipment 208, but to the upstream side, such as to the inlet of the compressor 202-2.